Sound-absorbing panel and method of making

ABSTRACT

A sound-absorbing panel is constructed, having first and second or inner and outer surfaces, with indentations in each surface that connect to each other via zones of communication. The indentations in the outer surface are divergent and generally circular in cross-section taken parallel to the outer surface. The indentations in the inner surface may be similar to the indentations on the outer surface, but preferably will comprise a series of parallel grooves. The indentations in the outer surface are constructed by simultaneously drilling a plurality of holes, preferably of frusto-conical configuration.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to sound-absorbing panels and in particular, to sound-absorbing panels that are perforated to allow soundwaves to pass therethrough, with the panels being generally adapted for use on interior ceilings, walls and the like, whereby sound in a room can be absorbed by passing through perforations in the panels, and preferably to be absorbed by sound-absorbing material disposed against an exterior surface of the panel.

[0002] It is known in the art to have sound-absorbing panels having perforations therethrough. For example, such panels are disclosed in U.S. Pat. No. 5,024,290, the complete disclosure of which is herein incorporated by reference. Other sound-absorbing panels are known having perforations therethrough, such as are disclosed in U.S. Pat. No. 5,422,446.

SUMMARY OF INVENTION

[0003] The present invention is directed to a sound-absorbing panel, in which sound is received in indentations on an inside, or first surface of the panel to pass through zones of communication between those first indentations and second indentations in an outer or second surface of the panel, but wherein sound passing through those second indentations in the outer surface of the panel can generally uniformly diverge between the zones of communication within the panel and the second, or outer surface of the panel, in that these second indentations are generally circular in cross-section parallel to the second or outer panel surface, and with the second indentations being simultaneously cut into the panel.

[0004] Another embodiment provides first and second indentations in opposite surfaces of the panel, which merge in zones of communication, and in which the indentations in each surface are grooves that are at acute angles relative to each other.

[0005] Accordingly, it is an object of this invention to make an acoustic panel having indentations in upper and lower surfaces connected by zones of communication, in which the indentations in the upper surface are simultaneously drilled therein, to be circular in cross-section, parallel to the upper surface, and divergent from the zones of communication to the upper surface.

[0006] It is another object of this invention to make an acoustic panel wherein indentations are provided in upper and lower surfaces, which communicate at zones of communication, as set forth in the objects above, and wherein the indentations in the lower surface comprise parallel grooves and the indentations in the upper surface comprise generally frusto-conical holes.

[0007] It is another object of this invention to accomplish the first stated object, wherein the indentations in the upper surface are generally conical, and within an angular range in cross-section, from 15° to 30°.

[0008] It is a further object that this invention to accomplish the objects above, wherein the indentations in the first surface are either of inverted V-shaped cross-section, inverted funnel-shaped cross-section, or of dome-shaped cross-section.

[0009] It is another object of this invention to accomplish the objects set forth above, by a method of making the panel such that the indentations in the second or the upper surface are drilled therein by bringing a plurality of rotating drills, mounted in a fixture, toward the second surface, to simultaneously drill the second indentations, to be generally circular in a cross-section.

[0010] Other objects and advantages of the present invention will be readily apparent upon the reading of the following brief descriptions of the drawing figures, detailed descriptions of the preferred embodiments, and the appended claims.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0011]FIG. 1 is a schematic longitudinal drawing of an apparatus for cutting grooves in a panel as it is transported along a longitudinal path, and then simultaneously cutting a plurality of frusto-conical holes in an opposite surface of the panel from that in which the grooves are cut.

[0012]FIG. 2 is a fragmentary plan view of a panel as shown in FIG. 1, taken generally along the line II-II of FIG. 1.

[0013]FIG. 3A is an end view of the panel shown in FIG. 2, taken generally along the line of III-III of FIG. 2, wherein the grooves in the first or inner surface of the panel are of inverted V-shape cross-section, with a gang drill being shown in phantom for simultaneously drilling holes in an opposite surface of the panel.

[0014]FIG. 3B is a view similar to that of FIG. 3A, but wherein the grooves are of funnel-shaped cross-section.

[0015]FIG. 3C is a view similar to that each of FIGS. 3A and 3B, but wherein the grooves are dome-shaped in cross-section.

[0016]FIG. 4 is an enlarged, fragmentary, transverse cross-sectional view of the panel of FIG. 2 taking generally along the line of IV-IV of FIG. 2, with sound-absorbing material and support members added to the panel of FIG. 2.

[0017]FIG. 5 is an enlarged, fragmentary, transverse cross-sectional view of a panel similar to that of FIG. 4, but wherein the indentations in the first, or inner surface of the panels are also frusto-conical in configuration, rather than of inverted V-shaped cross-section.

[0018]FIG. 6 is an enlarged fragmentary cross-sectional view of a pair of indentations in opposite surfaces of the panel of FIG. 4, wherein sound waves are shown converging from below the panel and diverging as they pass through the indentations in the upper surface of the panel, to be absorbed by the sound-absorbing material disposed thereagainst.

[0019]FIG. 7 is a view somewhat similar to FIG. 2, but wherein the indentations in the upper surface are comprised of parallel grooves.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS:

[0020] Referring now to the drawings in detail, reference is first made to FIG. 1 wherein a panel generally designated by the numeral 10 is shown as having been conveyed along a longitudinal path in the direction of the arrow 11, carried therealong on suitable rollers of a conveyor, having just passed a plurality of groove-cutting wheels 13 that are, in turn, mounted on a shaft 14 that is driven in the direction of the arrow 15, such that the cutting wheels 13 have just cut a plurality of spaced-apart parallel groves 16 in an inner or first surface 17 of the panel 10.

[0021] The panel 10 is then caused to be stopped in its horizontal motion in the direction of the arrow 11, such that a plurality of holes may be simultaneously drilled in a second or outer surface 18 of the panel.

[0022] The mechanism for drilling the holes comprises a plurality of drills 20 longitudinally spaced apart as shown in the direction of arrow 11, and spaced behind each other (not shown in FIG. 1 but shown in phantom in FIG. 3) rotationally driven, for example, in the direction of the arrows 21 via shafts 22 that are, in turn, driven through gears 23 that, in turn, are driven via a plurality of shafts 24 that, in turn, are driven by a motor 25 driven in the direction of the arrow 26 of FIG. 1.

[0023] The entire drill mechanism 27 comprising the shafts, gears and drills comprise a fixture 29 that is raised or lowered in the direction of the double headed arrow 28 by a suitable electric, pneumatic or like mechanism 30 for accomplishing the raising end lowering of the mechanism 27.

[0024] Thus, the drills 20 can simultaneously drill a plurality of holes 31 in the surface 18 of the panel 10, the centers of which are aligned with the apices 32 of the inverted V-shaped grooves 16 comprising the indentations in panel surface 17. The holes 31 comprise the indentations in the panel surface 18. The indentations 17 and 31 are in communication with each other via connecting zones of communication 33 as shown in FIG. 2.

[0025] The drills, thus configured as shown in FIG. 1 thereby create indentations 31 that are circular in a cross-section through the panel 10 taken parallel to the surface 18, and when viewed as shown in FIGS. 4-6 are frusto-conical in vertical transverse configuration, as dictated by the conically configured drill ends 34 defining an included angle “a” therebetween in vertical cross-section, that is within the range of 15°-30°, and more preferably within the range 25°-30°.

[0026] The zones of communication 33 are preferably about 1 mm² in parallel cross-section, as viewed in FIG. 2.

[0027] The apices 32 of the grooves 16 in the first surface 17 are preferably 5 mm apart, as are the centers of the drilled holes 31, along a given groove as shown in FIG. 2, and from groove-to-groove, also as shown in FIG. 2.

[0028] With reference now to FIG. 3A, it will be seen that the panel 10 has spaced-apart parallel grooves 16 that are of inverted V-shaped cross-section culminating in apices 32, as shown.

[0029] With reference to FIG. 3B, the panel 110 is shown to have inverted funnel-shaped grooves 116 in its first surface 117.

[0030] The panel of FIG. 3C represents another alternative embodiment to that of FIGS. 3A and 3B, but wherein it has dome-shaped grooves 211 in its first or inner surface 217.

[0031] Referring now to FIG. 4 it will be seen that a panel constructed in accordance with the description above for FIGS. 1, 2, and 3A is shown, generally designated by the numeral 10, but wherein a sound-absorbing material 40 is applied to the upper, or outer surface 18 of the panel, sandwiched between a support layer 41 and the panel 110, with a suitable frame type support 42 connecting the layers 41 and 10 together. The members 10, 41 and 42 can be fastened to each other by any suitable means, such as adhesives, staples, or the like, and may be of wood, masonite or various synthetic materials as may be desired. The sound-absorbing material 40 will preferably be of fiberglass insulation construction, but could be comprised of paper, glass wool, rock wool, cardboard or the like, as may be desired.

[0032]FIG. 5 represents another embodiment, generally similar to the embodiment of FIG. 4, but wherein the indentations 50 in the lower surface 51 of the panel 52 are drilled holes, circular in parallel cross-section to the surface 51, similar to the drilled holes 31 discussed above with respect to FIG. 2, such that upper and lower drilled holes 53 and 50, respectively, communicate via zones of communication 54 that are circular in cross-section parallel to the surfaces 51 and 55, for likewise converging sound waves entering the indentations 50 and diverging those sound waves as they pass through the indentations 53 into the sound-absorbing material 56.

[0033] Referring now to FIG. 6 it will be seen that there are schematically depicted sound waves 60 emanating from a source 61, that enter the indentations 16 in surface 17, and are caused to converge as they pass through the indentations 16 because of the shape of those indentations, with the soundwaves then passing through the zones of communication 33, to enter the diverging frusto-conical indentations 31 in the surface 18 of the panel 10, to be absorbed by the sound-absorbing layer of material 40 disposed against the surface 18.

[0034] Referring now to FIG. 7 it will be seen that the panel generally designated by the numeral 70 is constructed by making parallel grooves that comprise the indentations 71 in the lower or first surface, terminating in apices 72. In the upper surface there are also parallel spaced-apart grooves 73, terminating in downwardly facing apices 74, with the grooves 73 being at an acute angle b with the grooves 71, and with the grooves 73 and 71 each being cut into their respective surfaces at depths that are selected such that the apices 72 and 73 of the grooves on the opposite surfaces will intersect at zones of communication 75 that will permit soundwaves such as those described above with respect to FIG. 6, to enter the lower grooves 71, and to converge as they pass through the grooves 7 1, and to enter the upper grooves 73 in the upper surface via the zones of communication 75, with the soundwaves then diverging as they pass through the grooves 73, to be absorbed into a sound-absorbing material, such as fiberglass insulation or the like (not shown in FIG. 7), similar to the absorption of soundwaves discussed above with respect to FIG. 6.

[0035] The angle b may be any acute angle that will accomplish the purposes of this aspect of the invention, but will preferably be within the angular range of 30° to 60°, and preferably will be 45°.

[0036] The panels 10 and the like may be made of various materials, such as natural or synthetic wood, plastic, rubber, or any suitable material that will accomplish the purpose of the present invention of lending itself to construction of sound-absorbing panels of the type described, while presenting a large number of architectural styling capabilities.

[0037] It will be apparent from the forgoing that various modifications may be made in the details of construction, as well as in the use and operation of the panels of this invention and their method of manufacture, within the spirit and scope of the invention as defined in the appended claims. 

What is claimed:
 1. The method of making a sound-absorbing panel comprising the steps of: (a) providing a sheet of panel material having first and second generally parallel spaced-apart surfaces; (b) making first indentations in the first surface; and (c) making second indentations of generally circular cross-section in the second surface of the panel and of a depth to communicate with first indentations in the first surface at zones of communication, and with the second indentations being divergent from the zones of communication to the second surface; and (d) wherein the step of making second indentations comprises the step of simultaneously drilling a plurality of holes in said second surface to form the second indentations.
 2. The method of claim 1, wherein the step of simultaneously drilling comprises providing a gang of rotating drill bits mounted on a fixture for simultaneous movement toward and away from said second surface, and moving the fixture toward and away from the second surface while the drill bits are rotating, to drill the plurality of holes in the second surface.
 3. The method of any one of claims 1-2, wherein the drilling step comprises drilling a plurality of frusto-conical holes.
 4. The method of any one of claims 1-2, wherein the step of making first indentations comprises simultaneously cutting a plurality of generally parallel grooves in said first surface.
 5. The method of claim 4, wherein the cutting step comprises cutting grooves that are convergent from the first surface to the zones of communication.
 6. The method of claim any one of claims 1-2, including the step of applying a layer of sound-absorbing material to said second surface.
 7. The method of claim 6, including the step of applying a layer of support material to said layer of sound-absorbing material, to sandwich the later of sound-absorbing material between the second surface and the layer of support material.
 8. An acoustic panel made according to the method of any one of claims 1-2, comprising a sheet of panel material having first and second generally parallel spaced-apart surfaces defining therebetween the panel, with a plurality of first indentations in the first surface adapted to receive soundwaves; with a plurality of second indentations in the second surface; with a least some of the second indentations in the second surface having zones of communication with first indentations in the first surface to define through-holes through the panel; and with the second indentations being generally circular in transverse cross-section parallel to the second surface and being divergent from the zones of communication with the first indentations to the second surface; whereby soundwaves entering the first indentations pass through the zones of communication and diverge as they pass through the second indentations.
 9. The panel of claim 8, wherein the second indentations are generally frusto-conical in configuration.
 10. The panel of claim 9, wherein the second indentations have included angles in cross-section that are within the range of 15°-30°.
 11. The panel of claim 10, wherein the included angle is within the range of 25°-30°.
 12. The panel of any one of claims 8, wherein the first indentations are convergent from the first surface to the zones of communication with the second indentations.
 13. The panel of claim 12, wherein the zones of communication are approximately 1 mm² in transverse cross-section.
 14. The panel of claim 12, wherein the first indentations comprise a plurality of generally parallel grooves.
 15. The panel of claim 14, wherein the grooves are of generally inverted V-shaped cross-section.
 16. The panel of claim 15, wherein the groove centers are spaced apart approximately 5 mm.
 17. The panel of claim 14, wherein the grooves are of generally inverted funnel-shaped cross-section.
 18. The panel of claim 14, wherein the grooves are of generally dome-shaped cross-section.
 19. The panel of any one of claim 8, wherein the panel includes a layer of sound-absorbing material proximate the second surface, for absorbing sound as sound waves diverge through the second indentations.
 20. The panel of claim 19, wherein the panel includes a layer of support material against the layer of sound-absorbing material, sandwiching the layer of sound-absorbing material between the second surface and the layer of support material.
 21. An acoustic panel comprising a sheet of panel material having first and second generally parallel spaced-apart surfaces defining there between a panel; with a plurality of first indentations in the first surface adapted to receive soundwaves; with a plurality of second indentations in the second surface adapted to diverge soundwaves; with at least some of the second indentations in the second surface having zones of communication with first indentations in the first surface to define through-holes through the panel; and with the first indentations and the second indentations each comprising generally parallel spaced-apart grooves in their respective surfaces, with the grooves of the first and second indentations intersecting at acute angles to form the zones of communication; whereby soundwaves entering the first indentations pass through the zones of communication and diverge as they pass through the second indentations.
 22. The panel of claim 21, wherein said acute angles are within the range of 30° to 60°.
 23. The panel of claim 2, wherein the acute angles are approximately 45°. 